UPDATE: Please see Jefferson D. Tomas’ translation of this article.
The warning applies to any Swiss bank employee with access to customer data. They are being threatened with arrest in the US, France, Germany, Austria and Italy. However, the article writes that they are unlikely to be threatened with a punishment but rather that they may be called as witnesses.
Anwalt warnt Schweizer Banker vor Verhaftungen „Ich rate, das Land nicht zu verlassen“
FOCUS Online

I got a letter in the mail from the IRS stating that a request for transcript of tax return could not be processed because of my address across the sea. So, I called to correct the address, corrected it and then later got another letter from the IRS stating that my non-US address still didn’t match their records, which is still the case today.